The present invention relates to surgical methods and devices, and in particular to devices and methods for use in laparoscopic surgery. Laparoscopic, or “keyhole” surgery, is a well-known technique whereby elongate surgical instruments are inserted through one or more narrow incisions in the patient (typically 0.5 to 1.5 cm in diameter). Various instruments can be introduced into the patient in this way including scissors, graspers, cutters, energy dissection and sealing devices etc. The surgeon may pick and choose such instruments to suit his purpose. Laparoscopic surgery has several advantages compared to conventional open surgery. The smaller incisions result in reduced abdominal wall injury and hence lessened postoperative pain and wound complications. Patients typically will also have a shorter recovery time.
There are instruments which are critical to the success of any laparoscopic surgery, and which therefore tend to be used in every case and at nearly all times. For example, in order to hold a laparoscopic incision open, provide secure and sterile access to the patient and ensure a sealed space with sufficient pneumoperitoneum to enable working, a “port” or “trocar” containing an air valve is placed into each wound. Additionally the surgeon must have some feedback so he can guide his actions appropriately; in short, he must be able to see what he is doing. A laparoscope provides a suitable imaging mechanism, with currently known types comprising either a charge coupled device (CCD) for insertion directly into the patient or a telescopic lens system that brings the image out of the patient where it can be recorded with a camera. In addition, a fibre optic cable provides light so the laparoscope can be effective and a pump system insufflates the patient with an inert gas (e.g. carbon dioxide), so the instruments have space in which to move.
It is of course critical to the patient's wellbeing that any surgery is carried out in a safe and sterile manner. This principle is especially important when a laparoscopic operation involves the gastrointestinal tract as many of these procedures are ‘clean contaminated’ or potentially ‘contaminated’ (as defined by the US National Research Council group, see for example Berard F and Gandon J. “Postoperative wound infections: the influence of ultraviolet irradiation of the operating room and of various other factors” 1964 Ann. Surg. 160(Suppl 1) 1-192) and it extends to include any supplementary wounds which are required for the purposes of gastrointestinal specimen extraction, anastomosis formation or stoma creation as part of a laparoscopic operation. Therefore, when such incisions are made a wound protector is often placed into the body wall in order to protect the skin and subcutaneous tissues from microbiological contamination. In cases involving malignancy, this device also acts to shield the wound against tumour cell implantation. For patient benefit, these incisions are often made at the site of one or more of the laparoscopic trocars already made.
The advantages of laparoscopic operations can be maximized by reducing the number of incisions and recent progress in the field of laparoscopic surgery has resulted in many procedures being performed with just a single incision. This is particularly attractive when one larger incision is required anyway for the purposes of specimen extraction, anastomosis formation or stoma creation as maximising the utility of this wound may spare the patient any additional trocar wounds. However, while such surgery has benefits for the patient, the procedure is made more difficult for the surgeon due to the constraints inherent in performing surgery via a confined access.
Several different single incision laparoscopic ports to enable such working are currently available. For example, the “SILS port” (manufactured by Covidien®) comprises a narrow neck of solid plastic with a defined number of holes (three) machined into the plastic. The port is inserted into the incision, and has flanges at either end so that the port is held in place on either side of the incision. Tubes can then be inserted through the holes, and elongate surgical instruments inserted through the tubes to allow their access to the patient. The general construct of the outer interface is similar in other commercially available ports including those made by Advanced Surgical Concepts, Ethicon Endosurgery, Innovia, Applied Medical and Karl Storz. While some of these devices impose strict cylindrical or conical entry and parallel instrumentation, all (including the low profile devices) impose a fulcrum onto the individual trocars as well as a predetermined, fixed distance. Both of these factors significantly limit the freedom and independence of movement possible by the individual instruments and optic. In addition, all are supplied in kits that are restrictive in terms of available trocar number (limiting the number of instruments that can be used at any one time) and dimension (limiting the types of instruments that can be used at any one time) and tend to be exclusive of complementary tools that may be already available in a surgery department but made by a different manufacturer.
For example, many existing ports (such as Covidien's, described above) are manufactured with components comprising relatively hard plastic and have a defined number of access points for instruments. In addition the access points have a defined size, allowing only instruments of a certain diameter to be used. Surgeons therefore have to plan ahead within very narrow confines which instruments they will need for each particular part of the procedure. If a part of the procedure requires five instruments, say, and the port allows only four instruments to access the operating field at any one time, further incisions will be necessary. In addition, the surgeon's ability to improvise is lost (or at least hampered). For instance, he may need to stem excessive bleeding, but be unable to introduce either further instruments or instruments of greater calibre through the existing port. In addition, the relative hard nature of the construction material in currently available single ports limits the range of motion that is possible for the surgeon engaged in simultaneous instrument working—that is, the instruments are held at fixed distances at their fulcrum points in the device atrium. Furthermore, the fixed number of firm or rigid apertures which are moulded a fixed distance apart from each other (a feature common to many currently commercially available single port devices) imposes further constraints on the manoeuvrability and fluency of instrument movement and flow. Because of this firm nature of the material in which the bores or conduits for access are placed, the currently available ports tend also to contain the minimum number of extra conduits as additional non-used access sites further cramp the working space at the port. The only available device that allows maximum freedom of motion within it actually has no physical seal at the port (Airseal by Surgiquest) but is instead very large in its own diameter and physically restrictive.
Finally, all existing ports are relatively expensive. This dissuades medical authorities from authorising single-port laparoscopic techniques, in spite of the potential health benefits to patients and greatly restricts the opportunity for surgeons to gain expertise with these devices. The expense of these devices in practice also prohibits their use as adjuncts to standard multiport laparoscopic procedures (i.e. their use on any potential extraction wound site on a patient). For all these reasons, these devices tend to be used only in highly selected patients in selected centres rather than representing an additional capability for laparoscopic surgery more generally.